1. Retrieving
numerical values

2. Edit → Copy As → Spreadsheet (Tab delimited)
You can export your raw data from Gtplot or Xtplot into Excel
Edit → Copy As → Spreadsheet (Tab delimited)

3. Ctrl + v pastes your data.
x axis variable in the first column
y axis variables in subsequent columns

4. Text (Space delimited)
You can also export your data to a text editor in a nicely aligned table
Edit → Copy As →
Text (Space delimited)

5. Ctrl + v pastes your data.
x axis variable in the first column
y axis variables in subsequent columns